1. Field of Invention
This invention relates to a process for producing a pharmaceutical agent, in particular as an aerosol, with enhanced dosing accuracy, as well as a device for administering a pharmaceutical agent, in particular as an aerosol, with enhanced dosing accuracy.
2. Description of Related Art
In this invention, the term “pharmaceutical agent” is defined, in particular, as pharmaceutical agent formulations or pharmaceutical agent mixtures. The pharmaceutical agent is preferably present in liquid form, wherein it may be a suspension, a solution or a mixture of the two (a so-called suslution). In addition, it can be a powder. The following description of the invention focuses primarily on a pharmaceutical agent in liquid form, so that often only liquid is spoken of, but this correspondingly applies for other pharmaceutical agents, and for comparable substances, in terms of this invention.
European Patent Application EP 1 426 662 A1 and corresponding U.S. Patent Application Publication 2004/0134495, which forms the starting point of this invention, discloses a device for dosing or dispensing a liquid, in particular, a pharmaceutical liquid. The known device has a guide pipe with a piston that travels therein as well as an O-ring seal to ensure sealing between the guide pipe and piston. The O-ring seal is arranged in a groove of the guide pipe. To achieve a good seal, a groove fill level of more than 90% through the O-ring seal is provided. In practice, it has been shown that the tolerances of the individual components can lead to an inadequate seal, in particular against air, and thus, to an inadequate dosing accuracy. An exact dosage is essential, however, specifically in the administration of pharmaceutical agents or the like, to which this invention relates.